Electromagnetic flasher with lamp failure sensing means

ABSTRACT

An electromagnetic vehicle turn signal flasher in which lamps are lighted and a bulb outage relay is energized through normally closed contacts on operation of the turn signal switch. The relay armature operates to energize a timing relay, which deenergizes itself and momentarily opens the normally closed contacts to deenergize the outage relay and extinguish the lamps. The contacts, on reclosing, relight the lamps and energize the outage relay to repeat the cycle. The outage relay armature either does not operate or releases before the closed contacts have opened, if a lamp has failed, to maintain the dashboard indicator lamp continuously lighted for signalling the lamp failure. To enable the operated outage relay armature to release on lamp failure, the armature is held a predetermined distance from the core so that as the resistance of the remaining energized lamp filaments increases, the outage relay current decreases sufficiently to cause armature release.

[451 July 17, 1973 ELECTROMAGNETIC FLASHER WITII LAMP FAILURE SENSING MEANS [75] Inventors: Arthur .1. Little, Springfield; William R. Mayer, Rochester, both of 111.

[73] Assignee: Stewart-Warner Corporation, Chicago, Ill.

[22] Filed: Mar. 8, 1971 [211 App]. No.: 121,715

[52] US. Cl. 340/80, 335/89, 340/67, 340/81 F, 340/251 Primary Examiner-John W. Caldwell Assistant Examiner-Kenneth N. Leimer Attorney-Augustus G. Douvas, William .1. Newman and Norton Lesser [57] ABSTRACT An electromagnetic vehicle turn signal flasher in which lamps are lighted and a bulb outage relay is energized through normally closed contacts on operation of the turn signal switch. The relay armature operates to energize a timing relay, which deenergizes itself and momentarily opens the normally closed contacts to deenergize the outage relay and extinguish the lamps. The contacts, on reclosing, relight the lamps and energize the outage relay to repeat the cycle. The outage relay armature either does not operate or releases before the closed contacts have opened, if a lamp has failed, to maintain the dashboard indicator lamp continuously lighted for signalling the lamp failure. To enable the operated outage relay armature to release on lamp failure, the armature is held a predetermined distance from the core so that as the resistance of the remaining energized lamp filaments increases, the outage relay current decreases sufficiently to cause armature release.

3 Claims, 6 Drawing Figures [51] Int. Cl. B60q 1/38 [58] Field of Search 340/80, 81, 251, 340/252 [56] I References Cited UNITED STATES PATENTS 2,487,358 12/1969 Ubukata et a1 340/81 F 3,611,288 10/1971 Little et a1 340/81 F FORElGN PATENTS OR APPLICATlONS 669,834 8/1929 Francel 340/251 954,489 12/1956 Germany 340/81 324,572 1/1930 Great Britain 340/251 816,010 7/1959 Great Britain 340/81 1,121,869 7/1966 Japan 340/81 R .22 R1; RR

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INVENTORS Arthur J. Little W| lllorn R Mayer y a uza flornev PATENIED Jul 1' 7 sum 2 0r 4 FIG. 2.

INVENTORS Arthur J. Little William R. Moyer By A to INVE NTORS Arthur J. Lillle 6 I William R. Mayer By Allorney PAIENIE JUL 1 7 ma saw u or 4 an iallllllllllll FIG.5.{

INVENTORS Arthur a. Little William R. Mayer AHbrnev ELECTROMAGNETIC FLASHER WITH LAMP FAILURE SENSING MEANS BRIEF DESCRIPTION OF THE INVENTION Field of the Invention This invention relates in general to electromagnetic vehicle lamp flashers and more particularly to an im proved arrangement in an electromagnetic type vehicle lamp flasher for signalling lamp failure.

BACKGROUND OF THE INVENTION Electromagnetic vehicle flashers such as disclosed in copending U.S. application Ser. No. 785,861, filed Dec. 16, 1968, now US. Pat. No. 3,611,288, utilize a cyclically energized coil of a timing relay or electromagnetic actuator in series with the lamps for rotating an inertia weight through a gear train on operation of the turn signal switch. A pair of contacts cyclically operated in response to each coil energization, lights the vehicle lamps at a rate of 90 per minute with the total on-off periods averaging between 650 and 700 milliseconds at 50 percent on or off for each cycle. The on or off periods are relatively independent of battery voltage and variations in ambient conditions. The described flasher also utilized a current sensitive outage coil or winding in series with the turn signal lamps to provide a bulb outage indication in the event one or more lamps or bulbs failed. However, the bulb outage signal was provided by maintaining the dashboard indicator lamp continuously unlighted, which is unconventional, or complicated arrangements are required.

Additionally, the current sensitive bulb outage coil must distinguish between closely parallel situations in which a bulb has failed but the remaining lamps'initially pass as much current as if all lamps are operative. For example, two cold bulbs subject to a high battery voltage may pass as much current as three operating bulbs subject to a low battery voltage, especially if several of the three bulbs are subject to prior heating by operation of the brake switch. Further, operation of the bulb outage signal system must be disabled when the hazard switch is operated to flash all lamps without unnecessary wiring or excessively high current through the outage coil, resulting from the increased number of lamps connected to the coil.

SUMMARY OF THE INVENTION The present invention proposes to provide an economical vehicle bulb outage signal arrangement for an electromagnetic flasher of a type, such as described, in which the dashboard indicator lamp is maintained continuously lighted, and which provides a bulb outage signal when a lamp has failed despite the fact that the remaining lamps may draw as much current as if all lamps are lighted.

This is done by completing the lamp circuits through a current sensitive coil of an outage relay and a pair of normally closed contacts for lighting the bulbs. The coil energizes to attract its armature for energizing the timing relay, which drives the inertia weight to deenergize the timing relay and momentarily open the normally closed contacts to extinguish the lamps and deenergize the outage coil. The normally closed contacts close to relight the lamps and reenergize the outage coil for repeating the described procedure for flashing the lamps. If one of the lamps should fail, the outage relay coil will pass less current and fail to attract its armature. The

as the lamp filaments heat, it is feasible to distinguish between the condition wherein a plurality of lamps having an inoperative lamp pass as much current initially as a plurality of fully operative lamps. This is done by providing a relatively large air gap between the current sensitive outage relay coil and the attracted armature. The high initial current attracts the armature, but the return spring can restore the armature as soon as the current falls to a value characteristic of lamp failure. The armature carries a contact for engaging a flxed contact that in turn properly spaces the attracted armature from the outage relay core with the engaged outage relay contacts completing the circuit to the timing relay. The armature will therefore restore in the event of lamp failure to deenergize the timing relay and prevent the normally closed contacts from periodically opening so that the dashboard indicator lamp is held continuously lighted to signal the failure.

An additional coil wound on the outage relay core is connected in series with the outage relay coil to the lamps in response to operation of the hazard switch. The increased number of ampere turns on the outage relay core enables the outage relayarmature to be attracted for energizing the timing relay to flash the lamps despite the failure of a large number of lamps.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the flasher assembly and housing;

FIG. 2 is a top elevational view of the flasher;

FIG. 3 is a side elevational view of the flasher;

FIG. 4 is a sectional view taken along the line 44 in FIG. 3;

FIG. 5 is an isometric exploded view of the flasher; and

FIG. 6 is a circuit diagram illustrating the flasher circuit connected in a typical circuit for providing vehicle turn and hazard indications.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 of the drawings, a flasher assembly is indi cated by the reference character 10. The flasher assembly 10 is basically similar to that described in the aforementioned application and comprises a support card 12 of electrically insulating material.

The card supports an electromagnetic timing assembly l4 and a current sensitive relay assembly 16 encircled by a cup-shaped housing or can 18 fixed to the card 12 at the open end of the can. As best seen in FIG. 3, a plurality of terminals 19a, 19b, 19c and 19d fixed to card 12 enable the extension of electrical connections to the flasher assembly.

The timing assembly 14 includes an electromagnetic actuator or timing relay 20 having a core and coil 22 supported between the side legs of a U-shaped heelpiece 24 to which one end of coil 22 is electrically connected. An armature 26 is pivotally mounted at the end of one side leg of the heelpiece 24 for attraction to the coil 22 against the bias of a spring 28 in response to energization of the coil 22.

The armature 26 has an elongated arm 30 on which a contact 32 is located for engagement with a contact 34 carried on an upstanding arm 36 formed on a gear 38. The gear 38 is rotatably supported between card 12 and a second card 40 of electrically insulating material to which heelpiece 24 is fixed with card 40 spaced from card 12 by a plurality of spacers 41. The arm 36 and gear 38 are rotated by the armature 26 in response to energization of coil 22 for rotating a plurality of gears such as 42, 44 and 46 arranged in a gear train, as best seen in FIGS. 4 and and between cards 12 and 40 to in turn rotate an inertia weight 48 against the bias of a spring 50. The spring 50 is electrically connected at one end to a tab 52 on terminal 1% in parallel with a spring 53 and connects terminal 19b through gear 38, arm 36, contacts 34 and 32, armature 26 and heelpiece 24 to the one end of coil 22. Also fixed at one end to tab 52 is a cantilever spring 54 having a contact 56 at the other end for normally engaging a contact 58 fixed to card 12 by a U-shaped tab 59. A cam 60 in fixed association with gear 38 is adapted to engage spring 54 and separate contacts 56 and 58 after gear 38 is rotated a predetermined distance by armature 26.

The current sensitive or outage relay assembly 16 comprises a pair of serially connected coils 61 and 62, each approximately turns with a tap 64 between the coils 61 and 62 and each coil having substantially 0.0l5 ohms resistance. The tap 64 is connected to a tab 65 on terminal 19a while the opposite end of coil 61 is connected to contact 58 at tab 59 and the opposite end of coil 62 is connected to a tab 66 on terminal 190. The coils 61 and 62 are coaxially wound on a core 68 secured at one end to one horizontal leg of an L-shaped heelpiece 70 fixed to card 12 and electrically connected through card 12 to terminal 19d.

The other vertical leg of heelpiece 70 pivotally carries an L-shaped armature 72' biased to a normal or one position by a spring 74 with one leg 76 of the armature 72 spaced from core 68 by a predetermined distance of approximately 0.09 inch. The armature leg 76 has a downwardly bent projection 78 at its free end with the projection 78 carrying a contact'80 adjacent its free end and electrically connected through heelpiece 70 to terminal 19d.

A contact 82 carried by an insulator 84 adjacent the back leg of heelpiece 24 projects a fixed or predetermined distance above the heelpiece 24 is connected to the end of coil 22 opposite that connected to heelpiece 24. Contact 82 is adapted to be engaged by contact 80 in response to a predetermined current flow through coil 61 sufficient to move armature 72 toward core 68 to thereby connect terminal 191; through contacts 34 and 32, coil 22, contacts 80 and 82, armature 72 and heelpiece 70 to terminal 19d for the ing coil 22.

A typical vehicle circuit 100 in which the flasher is utilized for controlling the vehicle turn signal lamps is shown in FlG. 6. The circuit 100 generally includes at least one, and in this case two, rear turn signal lamps for each vehicle side indicated at RR and LR, respectively. These lamps RR and LR are conventionally lighted through respective break contacts 102 and 103 of a conventional turn signal switch TS and make contacts 104 of the brake switch on operation of the vehicle brake. In addition, a front turn signal lamps RF and purpose of energiz- LF, together with a respective dashboard indicator lamp RI and L1 is provided for each vehicle side. The dashboard indicator lamps RI and Ll pass current in the fraction of an ampere range, which is inconsequential as compared with the signal lamps RR, RF, LR and LF which pass current in the ampere range.

Operation of the turn signal switch TS to signal a right turn opens contacts 102 to open the circuit for operating lamps RR with the brake switch 104 and closes contacts 106 and 108 to connect ground through lamps RR, RF and RI through break contacts 110 of the hazard switch HS to tap 64 at terminal 1%. Operation of the turn signal switch TS to signal a left turn opens contacts 103 to open the circuit for operating lamps LR with the brake switch 104 and closes contacts 112 and 114 to connect ground through the lamps LR, LF and LI through break contacts 110 of the hazard switch to tap 64 at terminal 1%.

A hazard switch HS is provided for operating all of the vehicle signal lamps simultaneously and its operation opens contacts 110 to prevent the connection of any lamps to tap 64 at terminal 19a. Instead, the operated hazard switch HS connects the lamps RR and LR through contacts 102, 103 and 116 to tab 66 at terminal 190, while lamps RF and'Rl are connected through hazard switch contacts 118 to tab 66 and terminal 190 and lamps LR and L1 are connected through hazard switch contacts to tab 66 and terminal 190. Tab 66 in turn is connected to one end of coil 62.

On operation of the turn signal switch TS for either flashing the right or left turn vehicle lamps RR and RF or LR and LF, a circuit is completed from the power supply, terminal 191;, contacts 56 and 58, the outage relay coil 61, tap 64, terminal 19a and through the selected turn signal contacts, for example 106 and 108 or 1 12 and 114, to ground through the respective selected lamps RR and RF or LR and LF. A circuit for the re spective dashboard lamp R1 or L1 is also completed in parallel with the respective front turn signal lamp RF or LP, respectively, and all the selected turn signal lamps are lighted while coil 61 is energized in the described circuit.

With coil 61 energized, the armature 72 is attracted to the core 68 to close normally open contacts 80 and 82 and complete a circuit to coil 22 from the power supply, terminal 1% through coil 22, normally closed contacts 32 and 34 and contacts 80 and 82 to ground through terminal 19d. Coil 22 energizes to attract its armature 26 from its unoperated limit position to drive the arm 36 and gears 38, 42, 44 and 46 for rotating the inertia weight 48. When armature 26 reaches its operated limit position, contacts 32 and 34 separate, as the momentum of the gears and weight 48 continue to rotate arm 36 against the bias of spring 50 to open the circuit to coil 22. Armature 26 is therefore restored to normal under the bias of spring 28.

As the arm 36 rotates against the bias of spring 50, cam 60 engages blade 54 approximately 200 to 300 milliseconds after coil 22 is energized. Cam 60 engaging blade 54 opens contacts 56 and 58 immediately after contacts 32 and 34 open to open the circuit to the outage coil 61 and the lamps by separating contacts 56 and 58. The selected turn signal lamps therefore extinguish.

Thereafter, the momentum of the weight 48 and gears is dissipated and the spring 50 returns the gears and weight to normal. Contacts 56 and 58 therefore close under the bias of spring 54 as cam 60 disengages therefrom and contacts 32 and 34 thereafter close when arm 36 returns to normal. Contacts 56 and 58 are therefore only momentarily opened for a period of substantially 300 milliseconds and on closing again complete the circuit through coil 61 to the lamps for again lightingthe lamps and energizing coil 61. Energized coil 61 closes contacts 80 and 82 for again energizing coil 22 to repeat the aforedescribed operation for flashing the lamps.

Under normal circumstances, lamp failure will result in coil 61 passing insufficient current to attract armature 72 and close contacts 80 and 82. The relay 20 will therefore remain deenergized and contacts 56 and 58 remain closed to maintain the dashboard indicator lamp RI or Ll continuously lighted.

There are, of course, some cases in which the turn signal lamps, despite a failure, may initially pass as much current as a fully operative group of lamps. For

example, two cold lamps supplied with a battery volt-- turn signal switch can be operated in a few milliseconds and before the lamp filaments cool. The condition may be further aggravated by ambient temperature conditions. The coil 61 must therefore be capable of functioning normally or holding its armature attracted, when the three bulbs RR and RF or LR and LF are drawing a minimum current, which may be less than that initially drawn under some circumstances by only two of the three turn signal lamps.

To solve this problem the present invention takes advantage of the drop in current, which occurs about 150 to 200 milliseconds after the initial inrush current through the lamp filaments. Thus, the spacing of the armature 72 from core 68 is adjusted to operate armature 72 under the worst or lowest inrush current provided when all three vehicle turn signal bulbs are operative. This inrush current will normally be five to six times the steady state current which occurs after 150 to 200 milliseconds, when the filaments are warm. In the case where one lamp has failed and only two initially cold lamps are being lighted, the inrush current may be substantially higher than that described, but the steady state current will fall below that of three lighted lamps within the 150 to 200 milliseconds for heating the lamps. By limiting the movement of armature 72 to a position where it is spaced from core 68 by a distance 'which permits the armature to release in response to the lower steady state current through the two lamps, it is possible to signal the failure condition.

To illustrate the involved values, the force of spring 72, which is relatively constant, is indicated by the letter F and the magnetic circuit parameters which are likewise relatively constant are indicated by the letter C. Since the effect of the current is proportional to the square of the distance between the core 68 and armature 72, the force exerted by the current to operate the armature 72 or hold the armature operated is proportional to the ampere turns multiplied by magnetic circuit parameter C divided by the square of the initial gap or distance which is the sum of the working gap, 6 or distance which the armature moves and the final gap,

G,. For the worst initial inrush current condition in which it is desired to attract the armature, the magnetic force must be:

where F is the spring force and the number 12 is a factor corresponding to the inrush current for three warm lamps at a low battery voltage. if three lamps are lighted and armature 72 is in its operated position, the magnetic force required to hold the armature may fall to:

2.5C/G F where the number 2.5 is a factor corresponding to the steady state current for three warm lamps lighted at low battery voltage. When only two lamps are lighted, the maximum magnetic force, which permits armature to release, becomes:

where the number 2.2 is a factor corresponding to the steady state current.

To meet the lowest current condition in which three bulbs are lighted and still hold the armature 72 operated, it may be assumed that:

G,= 0.25 :L- V 0.0625 0.237/19 0.25 0.55/19 or G, 0.04 inch Therefore, by setting the initial gap between armature 72 and core 68 at 0.090 and the final gap at 0.040, the armature 72 will be operated initially whether three turn signal lamps are lighted or only two turn signal bulbs are lighted. Contact engaging contact 82 holds the armature 72 spaced from core 68 by a value corresponding to 6,. When the steady state. current is reached within 200 milliseconds after coil 61 is energized and three bulbs are lighted, the armature 72 will be held operated until contacts 56 and 58 operate as described for the normal condition. However, in the event only two bulbs are lighted, when the steady state current is reached the current through coil 61 will fall below the factor of 2.5 assigned above to the worst conto the gap distance squared, the magnetic force is less than the force of spring 74 and armature 72 restores to prevent full energization of coil 22. The distance G, may actually be as low as 0.02 inch and still provide both sufficient armature movement for closing contacts 80 and 82 and discriminate between the steady state current of three or two lighted bulbs.

Thus, when only two bulbs are lighted, their resistance increases within a short time of the energization of coil 61 to reduce the current flowing through coil 61. Coil 61, therefore, releases its armature before relay 20 is fully operated. Coil 22 will therefore fail to drive its armature 26 with sufficient force to open sets of contacts 32 and 34 and contacts 56 and 58, since contacts 32 and 34 open only slightly before contacts 56 and 58, which open approximately 200 milliseconds after coil 22 energizes and after coil 61 has energized and responded to current flowing in the lamp circuit. Failure of contacts 56 and 58 to open leaves the respective dashboard lamp continuously lighted to signal the bulb failure. Even if coil 22 should energize sufficiently to open contacts 32 and'34 and contacts 56 and 58, the force imparted to weight 48 will be insuff cient to fully cycle and the contacts 56 and 58 will reclose to energize the lamps before they cool, whereafter, the coil 61 will be unable to again attract the armature 72 for closing contacts 80 and 82. Coil 22 will thereafter remain deenergized and the lamps will remain continuously on to signal the failure.

in the event only one rear lamp RR or LR is provided so that a total of only two turn signal lamps RR and RF or LR and LF are provided for each vehicle side, a lamp or bulb failure results in a nominal 50 percent change in current. A current change of this magnitude is far more easily detectable than the nominal one-third current change in the three bulb situation and accordingly variations in battery voltage and lamp heating exert relatively smaller influence. The initial gap for armature 72 for a two lamp turn signal system, therefore, is easily adjusted to discriminate between the worst condition in which only one cold lamp is operative or two warm lamps at low voltage than in the three lamp situation described above.

To operate all of the vehicle turn signal lamps for signalling a hazard condition, switch HS is operated to open contacts 110 and disconnect tap 64 and terminal 19a from the turn signal switch TS. Contacts 116 close to connect the lamps RR and LR to terminal 19c; contacts 118 close to connect the lamps RF and Rl to terminal 19c; and contacts 120 close to connect the lamps LF and Ll to terminal 190. Terminal 19c connects the ground from the lamps through tab 66, coils 62 and 61 in series, contacts 56 and 58 to terminal 19!; and the power supply to light all the lamps. Coils 61 and 62 doubles the turns available for attracting armature 72. By placing coils 61 and 62 in series, the number of coil turns doubled, and the attraction of armature 72 to close contacts 80 and 82 is ensured irrespective of the fact that as many as five of the six lamps illustrated may fail.

Energization of coils 61 and 62 on operation of the hazard switch closes contacts 80 and 82 to energize coil 22. Energized coil 22 drives weight 48 and opens contacts 32 and 34 and contacts 56 and 58 to respectively deenergize coil 22 and coils 61 and 62, together with the lamps. Contacts 56 and 58 reclose to reenergize coil 22 and the aforedescribed procedure for flashing all of the lamps is repeated. In this case, however, since coils 61 and 62 provide double the number of ampere turns as coil 6] alone, the magnetic field for holding armature 72 greatly increases and up to five of the six lam ps may fail before armature 72 fails to hold contacts 80 and 82 closed for a sufficient period to fully energize coil 22.

The foregoing is a description of an improvedelectromagnetic flasher and bulb outage signal whose inventive concepts are believed set forth in the foregoing description and accompanying claims.

What is claimed is:

1. In a turn signal system having a plurality of vehicle turn signal lamps including a dashboard indicating lamp and having a vehicle turn signal switch operable for lighting said lamps with said lamps having a minimum initial inrush current irrespective of the failure of one of said lamps whereafter said inrush current falls in a predetermined time to either one value in response to all of said lamps being lighted or a second lower value in response to the failure of one of said lamps to light, the improvement comprising a relay having a first coil encircling a core, means including a first pair of contacts for energizing said relay coil in series with said lamps in response to operation of said turn signal switch, a biased armature for said relay attracted toward said core in response to the passage of at least said minimum inrush current by said lamps on energization of said coil, a stationary contact located in a predetermined position, a contact carried by said armature engaging said stationary contact in response to energization of said first coil with said stationary contact position spacing said armature a predetermined distance from said core whereby said armature is restored in said predetermined time only in response to said lamp current falling to said second lower value, a second coil, a second pair of normally closed contacts in series with said second coil for energizing said second coil in response to the closure of said armature and stationary contacts, rotatable means operated in one direction in response to the energization of said second coil for opening said second pair of contacts after said predetermined time to deenergize said second coil and thereafter opening said first pair of contacts to deenergize said first coil to extinguish said lamps and restore said relay armature, and means operated in response to the operation of said rotatable means in one direction for operating said rotatable means in the opposite direction for closing said first pair of contacts to reenergize said relay first coil and light said lamps in series with said first coil and for thereafter closing said second pair of contacts to energize said second coil in response to said armature contact engaging said stationary contact to reoperate said rotatable means, the restoration of said armature in response to said current falling to said second value in said predetermined time deenergizing said second coil to prevent opening of said first pair of contacts whereby said relay first coil is maintained continuously energized in series with said dashboard indicator lamp to maintain said dashboard lamp continuously lighted to signal the failure of said one lamp.

2. In the turn signal system claimed in claim 1 in which said armature is positioned substantially 0.04 inch from said core in response to engagement of said armature and stationary contacts.

3. In a turn signal system having a plurality of vehicle turn signal lamps including a dashboard indicating lamp and having a vehicle turn signal switch operable for lighting said lamps with said lamps having a minimum initial inrush current irrespective of the failure of one of said lamps whereafter said inrush current falls in a predetermined time to either one value in response to all of said lamps being lighted or a second lower value in response to the failure of one of said lamps to light, the improvement comprising a relay having a first coil encircling a core, means including a first pair of contacts for energizing said coil in series with said lamps in response to operation of said turn signal switch, a biased armature for said relay attracted toward said core in response to the passage of at least said minimum inrush current by said lamps on energization of said coil,

9 a stationary contact located in a predetermined position, a contact carried by said armature engaging said stationary contact in response to energization of said relay coil with said stationary contact position spacing said armature a predetermined distance from said core whereby said armature is restored in said predetermined time only in response to said lamp current falling to said second lower value, a second coil, means including a second pair of normally closed contacts in series with said second coil for energizing said second coil in response to the closure of said armature and stationary contacts, rotatable inertia weight means carrying one contact of said second pair and rotated from one position in response to energization of said second coil for opening said second pair of normally closed contacts after said predetermined time to deenergize said said coil while and weight means continues to rotate from said one position for thereafter opening said first pair of contacts to extinguish said lamps and deenergize said relay coil to restore said armature, and means for thereafter returning said weight means to said one position to close said first pair of contacts for enabling said lamps to relight in series with said first coil and then close said second pair of contacts to enable reenergization of said second coil, the restoration of said armature in said predetermined time in response to said current falling to said second value deenergizing said second coil to prevent opening of said first and second pairs of contacts whereby said relay coil is maintained continuously energized in series with said dashboard indicator lamp to maintain said dashboard lamp continuously lighted to signal the failure of said one lamp.

I I l 1. 

1. In a turn signal system having a plurality of vehicle turn signal lamps including a dashboard indicating lamp and having a vehicle turn signal switch operable for lighting said lamps with said lamps having a minimum initial inrush current irrespective of the failure of one of said lamps whereafter said inrush current falls in a predetermined time to either one value in response to all of said lamps being lighted or a second lower value in response to the failure of one of said lamps to light, the improvement comprising a relay having a first coil encircling a core, means including a first pair of contacts for energizing said relay coil in series with said lamps in response to operation of said turn signal switch, a biased armature for said relay attracted toward said core in response to the passage of at least said minimum inrush current by said lamps on energization of said coil, a stationary contact located in a predetermined position, a contact carried by said armature engaging said stationary contact in response to energization of said first coil with said stationary contact position spacing said armature a predetermined distance from said core whereby said armature is restored in said predetermined time only in response to said lamp current falling to said second lower value, a second coil, a second pair of normally closed contacts in series with said second coil for energizing said second coil in response to the closure of said armature and stationary contacts, rotatable means operated in one direction in response to the energization of said second coil for opening said second pair of contacts after said predetermined time to deenergize said second coil and thereafter opening said first pair of contacts to deenergize said first coil to extinguish said lamps and restore said relay armature, and means operated in response to the operation of said rotatable means in one direction for operating said rotatable means in the opposite direction for closing said first pair of contacts to reenergize said relay first coil and light said lamps in series with said first coil and for thereafter closing said second pair of contActs to energize said second coil in response to said armature contact engaging said stationary contact to reoperate said rotatable means, the restoration of said armature in response to said current falling to said second value in said predetermined time deenergizing said second coil to prevent opening of said first pair of contacts whereby said relay first coil is maintained continuously energized in series with said dashboard indicator lamp to maintain said dashboard lamp continuously lighted to signal the failure of said one lamp.
 2. In the turn signal system claimed in claim 1 in which said armature is positioned substantially 0.04 inch from said core in response to engagement of said armature and stationary contacts.
 3. In a turn signal system having a plurality of vehicle turn signal lamps including a dashboard indicating lamp and having a vehicle turn signal switch operable for lighting said lamps with said lamps having a minimum initial inrush current irrespective of the failure of one of said lamps whereafter said inrush current falls in a predetermined time to either one value in response to all of said lamps being lighted or a second lower value in response to the failure of one of said lamps to light, the improvement comprising a relay having a first coil encircling a core, means including a first pair of contacts for energizing said coil in series with said lamps in response to operation of said turn signal switch, a biased armature for said relay attracted toward said core in response to the passage of at least said minimum inrush current by said lamps on energization of said coil, a stationary contact located in a predetermined position, a contact carried by said armature engaging said stationary contact in response to energization of said relay coil with said stationary contact position spacing said armature a predetermined distance from said core whereby said armature is restored in said predetermined time only in response to said lamp current falling to said second lower value, a second coil, means including a second pair of normally closed contacts in series with said second coil for energizing said second coil in response to the closure of said armature and stationary contacts, rotatable inertia weight means carrying one contact of said second pair and rotated from one position in response to energization of said second coil for opening said second pair of normally closed contacts after said predetermined time to deenergize said said coil while and weight means continues to rotate from said one position for thereafter opening said first pair of contacts to extinguish said lamps and deenergize said relay coil to restore said armature, and means for thereafter returning said weight means to said one position to close said first pair of contacts for enabling said lamps to relight in series with said first coil and then close said second pair of contacts to enable reenergization of said second coil, the restoration of said armature in said predetermined time in response to said current falling to said second value deenergizing said second coil to prevent opening of said first and second pairs of contacts whereby said relay coil is maintained continuously energized in series with said dashboard indicator lamp to maintain said dashboard lamp continuously lighted to signal the failure of said one lamp. 